Esty's campaign bank account has more than $1 million and she raised $342,039.66 in the second three months of the year, her campaign said in a news release. Her campaign said she had never achieved this level of fundraising this early in a cycle.
"[She] attributes the strong showing to an overwhelming grassroots response to her being targeted for defeat earlier this year by the National Republican Congressional Committee," the campaign said.
The NRCC included Esty's central and northwestern Connecticut district on a list of three dozen "initial offensive targets" for the 2018 cycle back in February.
Esty's district has swung back and forth between Republicans and Democrats. She was narrowly elected to Congress in 2012 when the seat was vacated by Chris Murphy, who was running for the Senate.
After beating Andrew Roraback by 4 points in 2012, her re-election bids in 2014 and 2016 were by more comfortable margins.
Esty's complete financial report -- and reports for the rest of Connecticut's candidates for federal office -- will be filed with the Federal Election Commission by Saturday.
Republican Craig Diangelo of New Britain -- a former IT worker for Northeast Utilities -- has filed paperwork to challenge Esty and kicked off his campaign last month.